Hydrostatic washout tool



July 14, 1959 w. c. ERWIN HYDROSTATIC wAsHoUT Toor.

Filed Sept. l, 1954 United States Patent() "ice HYDROSTATIC WASHOUT TOOL Weldon C. Erwin, Los Angeles, Calif.

`Application September 1, 1954, Serial No. 453,603

6 Claims. (Cl. 166-43) This invention relates generally to oil well bore hole operations, and is particularly addressed to a method and apparatus for loosening and removing material which has become impacted between an operating string and the encircling bore hole wall.

In oil well operations, occasionally formations of sand, shale, clay, and the like will settle and accumulate around a portion of the operating string or particular tool being used. This accumulation may take the form of an annulus of impacted material between a particular stuck portion of the operating string and the encircling bore hole wall. In such a case, the stuck portion will be locked or clamped against any further rotational or vertical movement, thus, necessitating a costly stoppage of drilling or other oil well operations until the stuck portion can be loosened.

At present several methods are employed, with varying success, in an eiort to loosen and remove impacted material. In certain instances, the mere circulation of oil around the stuck portion will serve to loosen the impacted material. Another method used is to jar the operating string up or down, and there by attempt to loosen the stuck portion from the impacted material. In more troublesome cases, the operating string is backed E above the stuck portion, and a larger pipe is used to pass over and around the stuck portion in an attempt to drill and wash away the impacted material.

At best, these methods have only been an uncertain solution to the problem, and under certain conditions they may serve to even more securely lock the stuck portion of the operating string. For example, the jarring may aggravate the problem by causing more material to collect in the impacted area, or by shifting the impacted material in such a way that it settles more securely. Where a larger pipe is passed over the stuck portion, the larger pipe, itself, may become stuck. The oil circulation method will oftentimes not be successful, merely because the particular impacted material is not susceptible to oil lubrication. As the amount of solidication and the clamping action exerted by the impacted material on the stuck portion is not known, it may be necessary to try these and other methods, successively, until the impacted material is iinally worked loose.

In order that the operator may not be faced with a very costly and time consuming work stoppage, a method is needed which will, with reasonable certainty,

electively loosen the impacted material from the operating string in a relatively short time.

It is,`therefore, an object of the present invention to provide a method of loosening impacted material between a portion of an operating string and the bore hole 2,894,585 Patented July 14, 1959 wall that will be suitable for varying degrees of soliditication of the material, and which can be performed in a relatively short period of time.

- Another object is to provide a method and apparatus for loosening impacted material surrounding a stuck portion of operating string, which is effective in this objective without creating the possibility of aggravating the impacted condition.

Another object is to provide a method and apparatus for loosening impacted material surrounding a stuck portion of operating string having repetitively controlled steps applied according to the degree to which the mate- Irial is impacted. Y

These and other objects and advantages of this invention are attained by utilizing the hydrostatic pressure of the iiuid within the well to wash down through the impacted material and loosen it from the periphery of the stuck portion of operating string. The hydrostatic pressure of the fluid within the well is known to have been applied in regard to other operations involving sample taking devices, fishing tools, perforation cleaners, junk baskets, and the like. However, contrasting the methods now known, this invention along with its other features also involves a way of creating a low pressure area below (rather than above) the particular impacted material to be loosened and washed away. In brief, a low pressure area is created in a closed o free portion of the operating string, the free portion is then connected through a closure means to the stuck portion of the operating string, andthe closed off portion is opened transmitting the low pressure area through the stuck portion to the bottom levels of the layer of impacted material, and thereby creating a sudden pressure diiierential across the vertical thickness of the layer of impacted material. Preferably, the method is used in a repetitive manner, that is, repeatedly opening and closing the free portion of the pipe, in order to create the equivalent of a surging pressure wave through the impacted material.

A better understanding of this invention will be had by reference to the drawings, in which: i

Fig. l is a cut-away perspective view of a lower'section of a bore hole and'one type of apparatus for carrying out the method of loosening the impacted material;

Fig. 2 is a similar perspective view in which the apparatus has been operated to effect the loosening and Washing away of the impacted material; and,

Fig. 3 is an enlarged cut-away view of the portion of the device enclosed inthe circle 3 of Fig. 2.

In order that the preferred apparatus may be more readily comprehended, a preliminary discussion of the method, according to the invention, will be of value be- 'fore referring in detail to the parts shown in the drawings.

It will be assumed that a portion of an operating string or other tubular tool used in well operations has become stuck against movement because of impacted material forming between the particular stuck portion and the bore hole wall. The impacted material may have accumulated into a `formation iilling the annular cavity between the stuck portion and the bore hole wall. In such a case, the method to be described, will serve to create a sudden low pressure area that may be trans-` layer of impacted material. It will further be'assumedf as is usually the case in oil well drilling operations, that a column of circulating iluid is maintained in the bore hole, which will be exerting a hydrostatic force downwardly on the upper surface of the layer of impacted material. Upon the creation of the low pressure area transmitted downwardly through the stuck portion to the lower surface of the impacted material, a pressure differential will be established through the layer of impacted material because of the contrastingly high hydrostatic pressure on the upper surface of the impacted material. ln consequence, the material will be loosened away, and a violent surging and washing action will take place carrying the loosened material and liquid down to the end opening of the stuck portion, and then upwardly through the passage within the stuck portion and the remainder of the drill pipe or operating string.

In accomplishing this result, a stuck point gage or other apparatus is first run down into the well to ascertain the location of the stuck portion of the operating string, or the approximate stuck point may be determined by other means. After this point is determined, the operating string is separated at a location above the stuck portion or layer of impacted material. According to the particular components making up the operating string, this separation may be achieved by unthreading, uncoupling, or severing the two portions of the drill pipe, The part of the operating string not in contact with the impacted material, hereafter referred to as the free portion, is then removed from the well, and some form of closure means is attached to its bottom end. The free portion with the attached closure means is then run back into the Well and the lower end of the closure means is attached to the stuck portion of pipe. At this time the interior of the free portion will be at substantially atmospheric pressure, as it has been closed off from the fluid within the bore hole. The closure means is then suddenly opened, usually by a Vertical movement of the free portion of the drillpipe effected at the surface of the well. The low pressure area within the free portion will then suddenly be communicated through the stuck portion and out the `lower end thereof to the lower surface of the impacted material, and the previously described loosening action will take place. Preferably, the closure means comprises some type of valve mechanism in order that an effective pressure wave may be created through the impacted material by repeated opening and closing of the valve mechanism. Such a closure means is embodied in the apparatus shown in the drawings.

In Fig. l there is shown a bore hole l in which an operating string or drill pipe has been separated above a stuck portion. A closure apparatus for carrying out the method of this invention is indicated generally by the bracket ll, and, as shown, is interposed between the free portion l2 of the operating string, and the stuck portion i3.

Under the assumed conditions, the stuck portion is clamped against movement by the annular shaped formation of impacted material 14 confined by the bore hole Wall l5. Shown above the impacted material, is the circulating liquid or fluid i6. Usually the uid will permeate down through the impacted material.

The closure means l1 is threadedly connected by an upper joint 17 to the free portion l2, and by a lower joint 18 to the stuck portion 13. As mentioned previously, the joint ll8 might be made by other means known in the art, such as spear, overshot, or socket mechanisms.

Closure means il includes an upper movable portion and a lower stationary portion. The lower portion comprises a tubular section i9 connected through joint 18 to the stuck portion i3 of the operating string. This tubular section 19 has a reduced diameter at its upper end, defining a shoulder 20, and extending upwardly into a non-circular mandrel 2l terminating in a cylindrical packing head 22.

The upper movable portion of the closure means cornprises a telescoping section 23 including an upper coupling 24 connected at its upper end to the joint ll'7. The lower end of the telescoping section 23 threadedly receives an insert 25 spaced a given distance above shoulder 20 as shown in Fig. l. The insert 25 slidably receives the mandrel 2l, the packing head 22 riding within a packing chamber 26 in the telescoping section 23. The upper end of the insert 25 provides an annular stop 27 for engaging the lower end of packing head 22, when telescoping section 23 is moved upwardly. The telescoping section 23 is held in the position shown in Fig. 1 by shear pins 28 extending through the lower sidewalls of the insert into the mandrel 21.

Secured to the lower tubular section i9 is a ported tubular element 29, within which is rigidly secured a valve rod 30 extending upwardly through the element 29, mandrel 21, and packing head 22 to cylindrically shaped valve 31. Valve 31 is slidably received in a valve chamber 32 in the upper part of telescoping section coupling 24. In the position shown in Fig. l, the valve 3i in combination with the valve chamber 32, closes ott the free portion l2 of drillpipe from the fluid within the bore hole,

In operation, after the closure means lll has been interposed in the drillpipe to maintain atmospheric pressure in the free portion of the string, a part of the weight of the operating string is vertically applied to the upper telescopng section 23 by an operator at the ground surface of the well. Shear pins 28 will then be broken and the telescoping section 23 will slide down over the packing bead 22 until the lower end of insert 25 abuts the shoulder 20 of the lower tubular section i9. When this movement occurs, the telescoping section will be disposed in the position shown in Fig. 2.

In Fig. 2, the same reference numerals, as in Fig. l, have been used to designate similar parts. In this View, the valve chamber 32 has telescoped downwardly past the valve 3l, exposing openings 33 above the chamber to the annular passage around the valve rod 30. Through a similar movement of packing chamber 26 with respect to packing head 22, the packing head will now be disposed in an upper portion of the packing chamber. A continuous lluid passage then exists, as shown in Fig. 2 extending from the free portion l2 down through the openings 33 above the valve chamber, through the interior of the telescoping section 23, mandrel 2l, lower tubular section 19, and out through the ported element 29, through the stuck portion i3 to the bit opening 34- at the bottom end of the stuck portion. In consequence, the substantially atmospheric pressure within the free portion of the drillpipe, is transmitted to the lower surface of the impacted material 14.1. As this low pressure is transmitted upwardly through the impacted material, the material will be violently loosened and washed down to the bit opening 34 and up through the stuck portion and closure apparatus to the interior of the operating string l2 as indicated by the arrows.

After a brief interval of time, the free portion of the pipe and attached telescopng section 23 may be raised (since the shear pins 2S have been broken) and the valve 31 will enter the valve chamber 32 to assume position shown in Fig. 1 thereby closing the free portion of pipe 13 from entry of the Huid. As mentioned heretofore, the upward movement of telescoping section 23 will be stopped by the annular stop 2'7 at the upper end of the insert 25 coming into abutting contact with lower end of the packing head 22. An effort may then be made to move the drill pipe string by lifting or rotation and thereby ascertain whether or not the stuck portion has been loosened. If not, the telescoping section 23 is again dropped down onto shoulder 20 and the washing action repeated. By proper timing of the opening and closing of valve 3l in valve chamber 32, a surging pressure wave may be created throughout the vertical thick- :passassev ness of the impacted material 14. This surging pressure wave will be accompanied by a mechanical vibration throughout-the operating string, including the stuck portion, as the` fluid dynamically responds to the opening andfclosing of valve 3,1. In addition, the particular closure means ,1v1 will also function to exert a jarring force onstuck portion 413 when the telescoping section insert 25 collides withl shoulder 2,0 on the downward movement, and similarly whenv the annular stop of insert 25 collides with the lower end of the packing 22 on the upward movement. The ,opening and closing may be repeated untilj such time as the impacted material is thoroughly washed away or the stuck portion of the pipe effectively loosened.

It is apparent that after a given number of operations of opening and closing of the closure means 11, the pressure differential will finally be reduced to a nonetective value. It is, therefore, particularly important in the practice of this method, that the interval during which the closure means is opened be of short duration in order to prevent too much uid from entering into the free portion of the operating string 12.

In order that the hydrostatic head of the column of fluid in the bore hole may be kept at a maximum value, additonal iluid may be pumped into the bore hole at the surface of the well during the opening and closing of valve 31 in chamber 32.

As may be seen by reference to Fig. 3, the valve rod 30 may be hollow, openng at its upper end above the valve 31 and at its lower end below the ported element 29. The lower end of ported element 29 may be provided with a check valve 3S, embodying a ball 36 and a biasing spring 37. This check valve will normally be in the closed position, as shown, to prevent any uid from passing up through Ythe hollow rod 30, but will be opened by a downward fluid ow through the hollow valve rod 30, which has suilcient pressure to overcome the closing action exerted by spring 37 and the upward fluid pressure on the ball. This check valve acts as a one way bypass of the valve means comprising the valve 31 and chamber 32 and is particularly useful after the impacted material has been washed away, kand there is a necessity for reconditioning the well. In such a case, the uid may be pumped down through the interior of the operating string, with the closure means in the position shown in Fig. 1, by passing through the hollow rod '30, and hence through check valve 35 to the bit opening 34. In the event that valve rod 30 or the check valve 35 becomes clogged during the recirculation ofthe fluid, a blow-out plug 38, shown in Fig. 2 adjacent valve 31, may be provided to facilitate circulation through the operating string.

From the above description, it will be evident that the present invention provides a novel method and apparatus for loosening impacted material by establishng a pressure gradient through the vertical thickness of the material. This pressure gradient, together with the surging action and mechanical jarring, in accordance with the invention, will in most instances serve to remove the impacted material and free a stuck portion of an operating string.

What is claimed is:

1. In well drilling and producing operations, a method for loosening and removing a layer of material which has become impacted in the annular cavity between a portion of the operating string and the encircling bore hole wall, wherein the upper surface of said layer of material is subjected to the hydrostatic pressure of a uid column normally maintained in the bore hole, comprising the steps 'ofz separating the free portion of the operating string which is not in contact with said layer of material from the stuck portion of the operating string which is in contact with said layer of material; removing said free portion from its position within the bore hole;

closing otf'said free portion near its .bottom end; reposi-i tioning the free portion within the bore hole and sealably connecting said free portion to the top endA of said stuck v portion thereby maintaining substantially atmospheric pressure within the free portion; and instantaneously opening said free portion to transmit said atmospheric pressure downwardly through said stuck portion to a bit opening at the bottom of said operating string and vexpose said atmospheric pressure to the bottom surface 10 of said layer of material, thereby creating a sudden pressure differential throughout said layer of material and effecting a washing ofr said material through the stuck portion into the low pressure area within the free portion of the operating string.

2. The method according to claim 1, including the additional steps of: reclosing olf said free portion near its bottom end after a given interval of time; instantaneously reopening said free portion; and successively repeating the last two steps a given number of times, thereby creating a surging pressure wave washing through said layer of material.

3. The method according to claim 2, in which the stuck portion is mechanically vibrated and jarred during the opening, reclosing and reopening steps.

4. The method according to claim 1, including the additional step of: pumping suflcient uid into the bore hole to maintain a full head of uid in the annular cavity between the operating string and bore hole wall while the other steps of the method are performed.

5. In well drilling and producing operations, a method for loosening a portion of the operating string, which has become stuck because of a layer of material impacted between the stuck portion and the encircling bore hole wall, wherein the upper surface of said layer of material is subjected to the hydrostatic pressure of the uid normally maintained in the bore hole, comprising the steps of: separating the free portion of the operating string which is n'ot in contact with said layer of material from said stuck portion; removing said free portion from its position within the bore hole; closing off said free portion near its bottom end in order to maintain substantially atmospheric pressure within said free portion; repositioning the free portion within the bore hole and sealably connecting said free portion to the top end of said stuck portion; instantaneously opening said free portion to transmit said atmospheric pressure downwardly through said stuck portion to a bit opening at the bottom of said operating string and expose the bottom surface of said layer of material to said atmospheric pressure; reclosing said free portion after a given interval of time; instantaneously reopening said free portion; and successively repeating the last two steps a given number of times until the stuck portion is loosened by the surging pressure wave through the layer of material.

6. In well drilling and producing operations, an apparatus for interpositi'on between a stuck portion of an operating string surrounded by impacted material and a free portion of said string, wherein the upper surface of said impacted material is subjected to the hydrostatic pressure of a column of Huid normally maintained in the b ore hole, said apparatus comprising: a lower tubular sectron adapted to be sealably connected near its lower end to said stuck portion; an upper tubular section coupled to said lower section in telescoping relationship and adapted to be sealably connected at its upper end to the lower end of said free portion; a Valve chamber formed in said upper tubular section; a normally closed valve member seated in said chamber within said upper tubular section; an elongated rod forming a stem for said valve, said stem having its lower end secured within said lower tubular section and extending upwardly within said upper and said valve member being adapted to open in response to the telescoping of the upper section onto said lower section; and, co-operating means provided on said upper and lower sections for suddenly stopping said telescoping movement, whereby said atmospheric pressure is communicated through said stuck portion to a bit opening at the bottom of said operating string and thereafter to the lower surface of said impacted material to establish a pressure gradient through said material with respect to said hydrostatic pressure, and whereby a mechanical jar is transmitted to said stuck portion through said lower section each time said valve means is opened and closed.

UNITED STATES PATENTS Hill July 19, 1932 Abercrombie Nov. 22, 1932 Gates May 7, 1935 Flury July 26, 1938 Gates Dec. 6, 1938 Wickersham June 11, 1940 Mason Oct. 31, 1944 Lawrence May 29, 1945 Schabarum Oct. 17, 1950 Maxwell et al Jan. 27, 1953 

